Radar Cross Section (RCS)
Radar cross section is the effective area a target presents to a radar. In the optical (high-frequency) region — target much larger than a wavelength — a few canonical shapes have closed-form RCS. This tool gives the maximum (boresight) RCS of a sphere, flat plate, cylinder and trihedral corner reflector in both m² and dBsm, useful for calibration targets, link budgets and stealth intuition.
Equations & Parameters ▸
\(\text{Sphere: } \sigma=\pi a^2 \qquad \text{Flat plate }(a\times b): \sigma=\dfrac{4\pi (ab)^2}{\lambda^2}\)
\(\text{Cylinder }(a,L): \sigma=\dfrac{2\pi a L^2}{\lambda} \qquad \text{Trihedral }(a): \sigma=\dfrac{4\pi a^4}{3\lambda^2}\)
\(\sigma_{dBsm}=10\log_{10}\sigma \qquad \lambda=\dfrac{c}{f_0}\)
\(\text{Cylinder }(a,L): \sigma=\dfrac{2\pi a L^2}{\lambda} \qquad \text{Trihedral }(a): \sigma=\dfrac{4\pi a^4}{3\lambda^2}\)
\(\sigma_{dBsm}=10\log_{10}\sigma \qquad \lambda=\dfrac{c}{f_0}\)
| Shape | Canonical scatterer. Results are the maximum (boresight) RCS in the optical region (dimensions ≫ λ). |
| a | Primary dimension (m): sphere/cylinder radius, plate side, or corner edge length. |
| b / L | Second dimension (m): plate's other side, or cylinder length. Ignored for sphere and corner. |
| f0 | Frequency (GHz). Sphere RCS is frequency-independent in the optical region. |
Reference: E. F. Knott, J. F. Shaeffer & M. T. Tuley, Radar Cross Section, 2nd ed., 1993.
Inputs
rectangular plate
m
plate sidem
plate sideGHz
Radar bandResults
RCS
σ (linear)—
σ (dBsm)—
Wavelength λ—
Diagram